| refractory(adjective, tough, wild, awkward, obstinate) |
| touchy(adjective, delicate, awkward, irritable, tricky) |
| uncertain(noun, adjective, hard, severe, obscure) |
| effortful(adjective, hard, great, tough, rough) |
| agonizing(adjective, sickness, ache, anguishes) |
| cantankerous(adjective, hard, tough, evil, rough) |
| challenging(adjective, hard, great, tough, obscure) |
| compound |
| dangerous(noun, adjective, hard, tough, severe) |
| fatiguing(adjective, dull, awkward, boring, tired) |
| harsh(adjective, hard, tough, severe, rough) |
| nit-picking |
| picky(adjective, tough, harsh, particular, meticulous) |
| problem(noun, adjective, hard, tough, grim) |
| problematical(adjective, hard, complex, awkward, demanding) |
| recalcitrant(adjective, tough, wild, awkward, obstinate) |
| risky(noun, adjective, delicate, awkward, tricky) |
| tiresome(adjective, hard, tough, severe, heavy) |
| unyielding(adjective, hard, tough, severe, wild) |
| wearisome(adjective, dull, hard, tough, rough) |